Once again, Cisco is pushing out cloud predictions. The company just released its third annual Global Cloud Index, which forecasts that global cloud -- the fastest growing component of data center traffic -- is expected to quadruple in the next four years.

If Cisco’s numbers hold up, that marks a 35 percent combined annual growth rate, from 1.2 zettabytes of annual traffic in 2012 to 5.3 zettabytes by 2017. By contrast, overall global data center traffic will grow threefold and reach a total of 7.7 zettabytes annually by 2017.

A zettabyte is one billion terabytes. For context, 7.7 zettabytes is equivalent to: 107 trillion hours of streaming music (about 1.5 years of continuous music streaming for the world's population in 2017); 19 trillion hours of business web conferencing (about 14 hours of daily web conferencing for the world's workforce) in 2017; or 8 trillion hours of online high-definition video streaming (about 2.5 hours of daily streamed HD video for the world's population in 2017).

Surfing on the Cloud

"People all over the world continue to demand the ability to access personal, business and entertainment content anywhere on any device, and each transaction in a virtualized, cloud environment can cause cascading effects on the network," said Doug Merritt, senior vice president of Product and Solutions Marketing at Cisco. "Because of this continuing trend, we are seeing huge increases in the amount of cloud traffic within, between and beyond data centers over the next four years."

Cisco predicts about 17 percent of data center traffic will be fueled by end users accessing clouds for web surfing, video streaming, collaboration and connected devices, all of which contribute to the Internet of Everything, which is the networked connection of people, data, process and things.

Other data center traffic is not caused directly by end users, the firm said, but by data centers and cloud-computing workloads used in activities that are virtually invisible to individuals. For the period from 2012 to 2017, Cisco forecasts that 7 percent of data center traffic will be generated between data centers, primarily driven by data replication and software/system updates. An additional 76 percent of data center traffic will stay within the data center and will be largely generated by storage, production and development data in a virtualized environment.

The Mobile Factors

We caught up with Zeus Kerravala, a principal analyst at ZK Research, to get his thoughts on the report. He told us this data shows that virtualization technology has reached a tipping point, and IT has confidence to run mission critical workloads on virtual servers.

“A few years ago if you talked to a lot of CTOs and CIOs, there’s no way they would have run any kind of mission critical app on a virtual server. But today it’s very commonplace. We are finally at a point where it shouldn’t surprise you to see any company run almost all their workloads in a virtual environment,” Kerravala said.

“If you are going to run it in a virtual environment then the next step is to run it in some type of cloud delivery model. It fits the virtual methodology better. Mobility is the other big tipping point here. When you think of computing, it’s a network-centric compute model and cloud is a better delivery model for mobile. To me cloud and mobile go hand in hand, very much like cake and ice cream,” he said.